Whenever I try to open any files I get the error messages "StaadFoundation MFC Application has stopped working" / "Attempted an unsupported operation".
Right click on STAAD.foundation Advanced icon (short-cut) and select the option "Run as administrator". Open a file and see if the issue is resolved.
If not, download the latest version of the software. Follow the software downloads instructions as mentioned in the following link
https://communities.bentley.com/communities/other_communities/sign-in_assistance_and_web_services/w/wiki/30658/software-download-instructions
Once downloaded, uninstall the software from Control Panel -> Programs and Features menu.
Now, right -click on the downloaded file and select the option "Run as administrator" (though you may be logged in as the administrator).
Once done, right-click on STAAD.Foundation Advanced icon (short-cut) and select the option "Run as administrator" to make sure all the settings are done correctly.